10 Infectious Disease Developments That Defined Q2 2026

The second quarter of 2026 delivered a remarkable concentration of regulatory milestones, outbreak events, and pipeline advances across infectious disease. From the first-ever US approval for hepatitis delta virus to landmark HIV treatment options and a cruise ship outbreak that put the country's biopreparedness infrastructure to the test, the April–June period was among the most consequential quarters for the field in recent memory. The Contagion team covered each development as it unfolded. Here is a summary of 10 of the most significant stories from Q2 2026.